System amd method for bone fusing implants

ABSTRACT

A bone fusing implant device includes an elongated body extending along a longitudinal direction, and has one or more elongated grooves extending along the longitudinal direction on an outer surface of the elongated body and one or more elongated ridges alternating with the one or more elongated grooves and extending along the longitudinal direction on the outer surface of the elongated body. The elongated body includes a first segment having an outer surface with cortical threads, a second segment having an outer surface with cancellous threads, a top segment and a bottom segment. The first segment is configured to engage a cortical bone with the cortical threads and the second segment is configured to engage a cancellous bone with the cancellous threads. The cortical threads and the cancellous threads are formed on the one or more elongated ridges and do not extend into the one or more elongated grooves.

CROSS REFERENCE TO RELATED CO-PENDING APPLICATIONS

This application is a continuation-in-part and claims the benefit ofU.S. application Ser. No. 16/515,477 filed Jul. 18, 2019 and entitled“SYSTEM AND METHOD FOR BONE FUSING IMPLANTS”, the contents of which areexpressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a system and a method for bone fusingimplants, and more particularly to bone fusing implants that are usedfor sacroiliac joint fusion.

BACKGROUND OF THE INVENTION

The human spine includes individual vertebras that are connected to eachother. Under normal circumstances the structures that make up the spinefunction are configured to protect the neural structures, allow us tostand erect, bear axial loads, and are flexible for bending androtation. Disorders of the spine occur when one or more of these spinestructures are abnormal. In these pathologic circumstances, surgery maybe tried to restore the spine to the normal state and to relieve thepatient of pain. Spine surgery for a multitude of spinal disorders isoften used for filling voids within a pathologic vertebral body(exemplified by kyphoplasty or vertebroplasty procedures), replacementof a degenerated intervertebral disc with an intervertebral implantdevice that preserves mobility (disc replacement) or for fusing adjacentvertebral segments (interbody and posterolateral fusions). Fusion workswell because it stops pain due to movement at the joints, holds thespine in place after correcting a deformity, and prevents instabilityand or deformity of the spine after spine procedures such aslaminectomies or verterbrectomies.

One area where fusion is applicable is for sacroiliac joint fusion(SIJF). The sacroiliac joint (SIJ) is a firm, small joint that lies atthe junction of the sacrum and the pelvis. While most of the vertebrasof the spine are mobile, the sacrum is made up of five vertebras thatare fused together and do not move. The iliac bones are the two largebones that make up the pelvis. The sacroiliac joints connect the spineto the pelvis. The sacrum and the iliac bones are held together by acollection of strong ligaments. These joints are important intransferring the load of the upper body to the lower body, supportingthe entire weight of the upper body when we are erect, which in turnresults in stress to this weight-bearing area of the pelvis and spine.Pathologies of the SIJ include degenerative sacroiliitis (arthritis),sacroiliac disruption, tumors and other type of injuries. Sacroiliacjoint (SI) fusion is used for treating degenerative sacroiliitis,sacroiliac disruption, and for stabilizing the SI joint after sacrectomyor after injury.

There is increasing consensus among surgeons that there is a need todevelop devices, instruments, and methods to limit the size of theincision, extensive muscle stripping, prolonged retraction of musclesfor visualization, avoidance of neural tissue retraction and injury, anddenervation and devascularization that are known to contribute to poorerpatient outcome after traditional open surgeries to treat pathologiesdeep within the body. In many cases these complications lead topermanent scarring and pain that can be more severe than the pain fromthe initial ailment. Limiting these complications in addition to theoperative, general anesthesia, and recovery times are among the goals ofthis invention and that of percutaneous or minimally invasive surgeries.

This invention addresses the need for bone fusing implants that are usedfor sacroiliac joint fusion and for implant insertion tools that adhereto the principals of the less exposure surgery (LES) of outpatientsurgery, which include minimizing the size of the incision, minimizingextensive muscle stripping, minimizing prolonged retraction of musclesfor visualization, and preventing neural tissue retraction and injury.

SUMMARY OF THE INVENTION

The present invention relates to a system and a method for bone fusingimplants, and more particularly to bone fusing implants that are usedfor sacroiliac joint fusion.

In general, in one aspect, the invention features a bone fusing implantdevice including an elongated body extending along a longitudinaldirection, and comprising one or more elongated grooves extending alongthe longitudinal direction on an outer surface of the elongated body andone or more elongated ridges alternating with the one or more elongatedgrooves and extending along the longitudinal direction on the outersurface of the elongated body. The elongated body includes a firstsegment having an outer surface with cortical threads, a second segmenthaving an outer surface with cancellous threads, a top segment and abottom segment. The first segment is configured to engage a corticalbone with the cortical threads and the second segment is configured toengage a cancellous bone with the cancellous threads. The corticalthreads and the cancellous threads are formed on the one or moreelongated ridges and do not extend into the one or more elongatedgrooves.

Implementations of this aspect of the invention may include one or moreof the following features. The top segment is adjacent to the firstsegment along the longitudinal direction and has an outer surface withcortical threads that are thicker than the cortical threads of the firstsegment. The bottom segment is tapered and adjacent to the secondsegment along the longitudinal direction and has a self-cutting tip. Theelongated body further includes a central opening extending along thelongitudinal direction through the elongated body's center. The centralopening has a top portion and a bottom portion and the bottom portionhas a smaller diameter than the top portion. The elongated body furtherincludes one or more through-openings that extend horizontally andintersect with the central opening. The elongated body has a star-shapedcross-section and the elongated grooves are arranged 60 degrees apartfrom each other around the elongated body. The first segment has alength equal to the cortical bone's length and the second segment has alength equal to the cancellous bone's length. The elongated grooves havea porous structure. The elongated body further includes bone materialinserted into the top portion of the central opening and funneledoutwardly through the one or more horizontally extending openings. Thebone material comprises one of bone graft, bone putty, stem cells,autograft bone, or allograft bone. The elongated body comprises one ofbone, polyetheretherketone (PEEK), Nitinol, metals, titanium, steel,metal composites, biodegradable materials, collagen matrices, syntheticpolymers, polysaccharides, calcium minerals, calcium salts, orcomposites containing calcium or phosphorous naturally or man-made.

In general, in another aspect, the invention features a method for bonefusing including the following. First, providing an implant devicecomprising an elongated body extending along a longitudinal direction.The elongated body comprises a first segment having an outer surfacewith cortical threads, and a second segment having an outer surface withcancellous threads. Next, engaging a cortical bone with the corticalthreads of the first segment and then engaging a cancellous bone withthe cancellous threads of the second segment. The elongated bodyincludes one or more elongated grooves extending along the longitudinaldirection on an outer surface of the elongated body and one or moreelongated ridges alternating with the one or more elongated grooves andextending along the longitudinal direction on the outer surface of theelongated body. The cortical threads and the cancellous threads areformed on the one or more elongated ridges and do not extend into theone or more elongated grooves.

Implementations of this aspect of the invention may include one or moreof the following features. The method further includes forming anopening extending into the cortical bone and the cancellous bone andinserting and threading the implant device into the opening in order toengage the cortical bone with the cortical threads of the first segmentand the cancellous bone with the cancellous threads of the secondsegment. The method further includes impacting a broach into the openingto generate an opening pattern matching the cross-section of theelongated body prior to inserting and threading of the implant deviceinto the opening. The opening is formed by drilling a pilot opening intothe cortical bone and the cancellous bone and then inserting andthreading the implant device into the pilot opening. The method furtherincludes using a tap to tap threads in the opening prior to insertingand threading the implant device into the opening.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and description below. Other features,objects, and advantages of the invention will be apparent from thefollowing description of the preferred embodiments, the drawings, andthe claims

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the figures, wherein like numerals represent like partsthroughout the several views:

FIG. 1A is a schematic side view of an embodiment of a bone fusingimplant that is used for fusing two adjacent bones, according to thisinvention;

FIG. 1B is a schematic side view of another embodiment of a bone fusingimplant that is used for fusing two adjacent bones, according to thisinvention;

FIG. 2A is a perspective view of the bone fusing implant of FIG. 1A;

FIG. 2B is a cross-sectional view of the bone fusing implant of FIG. 2Aalong plane A-A′;

FIG. 3A is a perspective view of the bone fusing implant of FIG. 1B;

FIG. 3B is a cross-sectional view of the bone fusing implant of FIG. 3Aalong plane A-A′;

FIG. 3C is a cross-sectional view of the bone fusing implant of FIG. 3Aalong plane B-B′;

FIG. 3D is a top view of the bone fusing implant of FIG. 3A;

FIG. 4A is a top perspective view of a bone fusing peg implant,according to this invention;

FIG. 4B is a bottom perspective view of the bone fusing peg implant ofFIG. 4A;

FIG. 4C is a side view of the bone fusing peg implant of FIG. 4A;

FIG. 4D is a top view of the bone fusing peg implant of FIG. 4A;

FIG. 4E is a cross-sectional view of the bone fusing peg implant of FIG.4A along plane A-A′;

FIG. 5A-FIG. 5C depict side views of other embodiments of the bonefusing peg implant;

FIG. 6A is a schematic posterior view of the pelvic bones and sacrumheld together by two inserted bone fusing implants;

FIG. 6B is a schematic posterior view of the pelvic bones and sacrumindicating the two bone fusing implants as they are being inserted;

FIG. 6C is a schematic side view of the pelvic bones and sacrumindicating the two bone fusing implants as they are being inserted;

FIG. 7 depicts a pin guide tool;

FIG. 8A is a perspective view of another embodiment of a bone fusingimplant;

FIG. 8B is a side view of the bone fusing implant of FIG. 8A;

FIG. 8C is a top view of the bone fusing implant of FIG. 8A;

FIG. 8D is a bottom view of the bone fusing implant of FIG. 8A;

FIG. 9A is a perspective view of yet another embodiment of a bone fusingimplant;

FIG. 9B is a side view of the bone fusing implant of FIG. 9A;

FIG. 10A is a schematic posterior view of the pelvic bones and sacrumdepicting four SIJ intra-articular bone openings;

FIG. 10B is a schematic perspective posterior view of the pelvic bonesand sacrum depicting the insertion of the bone fusing implant of FIG. 8Ainto one of the intra-articular openings of FIG. 10A;

FIG. 10C is a schematic posterior view of the pelvic bones and sacrumdepicting the inserted fusing implant of FIG. 8A into one of theintra-articular openings of FIG. 10A;

FIG. 10D is a schematic side view of the pelvic bones and sacrumindicating the inserted bone fusing implant of FIG. 8A into one of theintra-articular openings of FIG. 10A;

FIG. 11A is a schematic posterior perspective view of the pelvic bonesand sacrum depicting an opening extending across the SIJ;

FIG. 11B is a schematic posterior perspective view of the pelvic bonesand sacrum held together by a bone fusing implant of FIG. 9A insertedinto the opening of FIG. 11A across the SIJ;

FIG. 11C is a schematic posterior perspective view of the pelvic bonesand sacrum held together by the bone fusing implant of FIG. 9A insertedinto the opening of FIG. 11A across the SIJ;

FIG. 11D is a schematic side view of the pelvic bones and sacrumindicating the inserted bone fusing implant of FIG. 9A into the openingof FIG. 11A across the SIJ;

FIG. 12A is a cross-sectional view of the broach profile of the openingof FIG. 11A;

FIG. 12B is a cross-sectional view of the bone fusing implant of FIG. 9Ainserted into the opening of FIG. 11A.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a system and a method for bone fusingimplants, and more particularly to bone fusing implants that are usedfor sacroiliac (SI) joint fusion.

Referring to FIG. 1A, FIG. 1B, FIG. 6A-FIG. 6C, in SIJF surgery one ormore openings 92 are formed along the arrow direction 81 and bone fusingimplants 100A, 100B, 200, 400, or 500 are inserted in the formedopenings 92. Referring to FIG. 1A, bone fusing implant 100A is insertedin opening 92 that is formed through two stacked adjacent bone members90 a and 90 b. In one example, bone member 90 a is primarily a cortical(compact) bone and bone member 90 b is in majority a cancellous (porous)bone.

Referring to FIG. 2A and FIG. 2B, bone fusing implant 100A includes acylindrical hollow threaded body 110 that has three elongated slitopenings 112 (fusion gutters), a central through opening 122 thatextends the entire length of the implant, horizontally extendingthrough-openings 115, a first segment 130 with cortical threads 132, asecond segment 140 with cancellous threads 142, a top segment 120 thatis tapered and has threads 125 that are thicker than the corticalthreads 132, and bottom tip segment 145 that is tapered andself-cutting. Cortical threads 132 are closely spaced. Screws withcortical threads are used for fixation of cortical (compact) bone.Cancellous threads 142 are widely spaced. Screws with cancellous threadsare designed for fixation of cancellous (porous) bone. Since cancellousbone is much less dense than cortical bone, the screw threads are spacedfurther apart, leaving space for more bone in between each thread. Inone example, implant 100A has a length of 35 mm and a diameter of 12 mm.The segment 130 with the cortical threads 132 has a length of 15 mm,which corresponds to the width of the cortical bone 90 a. The segment140 with the cancellous threads 142 has a length of 20 mm, whichcorresponds to the width of the cancellous bone 90 b. Slit openings 112are arranged 120 degrees apart and cut through the screw threads 132,and intersect at the top end with the horizontally extendingthrough-opening 115. Central opening 122 includes a top portion 122 aand a lower portion 122 b and the lower portion 122 b has a smallerdiameter than the top portion 122 a. The horizontally extendingthrough-openings 115 intersect with the top portion 122 a of the centralthrough opening 122 and allows slit openings 112 to communicate with thethrough-opening 122.

The top portion 122 a of the through-opening 122 is used for insertingbone material, such as bone graft, bone putty, stem cells, autograft,and allograft, among others, into the central through-opening 122 andthen funneling the bone material outward through the three horizontalthrough-openings 115 along the three slit openings (fusion channels) 112to aid fusion across the SI joint. In other examples, bone implant 100A,has a length of 60 mm and includes a slit opening 112 that has a lengthof 23.1 mm. Bone implant 100A is made of bone, polyetheretherketone(PEEK), Nitinol, metals, titanium, steel, metal composites,biodegradable materials, collagen matrices, synthetic polymers,polysaccharides, calcium minerals, calcium salts, or compositescontaining calcium or phosphorous naturally or manmade.

Referring to FIG. 3A-FIG. 3D, in another embodiment, bone implant 100Bincludes a cylindrical hollow threaded body 160 that has a centralthrough opening 162 that extends the entire length of the implant, afirst segment 130 with cortical threads 132 and a second segment 140with cancellous threads 142. Body 160 also includes a top segment 120that is tapered and has threads 125 that are thicker than the corticalthreads 132, and a bottom tip segment 145 that is tapered andself-cutting. The tapering of the top segment portion 120 refers to theminor diameter of the screw tapering up(growing) as it gets closer tothe proximal end. This tapering causes compression via an increasinginterference between the screw and the pilot-hole. Central opening 162includes a top portion 162 a and a lower portion 162 b and the lowerportion 162 b has a smaller diameter than the top portion 162 a. In thisembodiment, the cylindrical body includes three slit openings 172 a, 172b, 172 c (lattice gutters) that are arranged 120 degrees apart. Slitopenings 172 a, 172 b, 172 c do not cut through the outer threads 132and 142 and communicate at the top end with the top portion 162 a of thecentral through opening 162. Slit openings 172 a, 172 b, 172 c include alattice structure 152 and may be filled with bone growth medium. Thebone growth medium may be bone, putty, stem cells, or bone graft, amongothers. The bone graft medium may be inserted via the central opening162, or the slit openings 172 a, 172 b, 172 c either before or afterimplantation. The top surface of the elongated body includes a six-lobeshaped structure 163 that is used for receiving a driver tool. Boneimplant 100B is manufactured using “additive manufacturing” techniques,such as electron beam melting (EBM), and direct metal laser sintering(DMLS), among others.

Referring to FIG. 4A-FIG. 4E, in another embodiment, bone fusing implant200 includes a star-shaped hollow elongated body 210 that has a centralthrough opening 212, outer ridges 214 and slit openings 216 a, 216 b.The star-shaped elongated body 210 has increased outer surface area dueto the surface areas provided by ridges 214, shown in FIG. 4A and FIG.5A and FIG. 5B. The increased outer surface area contributes to betterjoint fixation by minimizing micro-motion and therefore improving bonefusion. In one example, implant 200 has a length of 45 mm, a diameter of15.5.mm and is made of a titanium rod. The outer surface 216 of theimplant 200 may be coated with bone growth enhancing additives such ascalcium phosphates, hydroxyapatite, or similar, which provides atextured porous surface 216, as shown in FIG. 4A and FIG. 5C. Theimplant 200 is coated via plasma evaporation, sputtering or electronbeam melting. Sections 216 a and 216 b of the implant 200 may beadditively manufactured to form a trabecular or lattice structure 215,as shown in FIG. 5A and FIG. 5B. In another embodiment, implant 200 doesnot have any slit openings 216 a, 216 b or other internal cavities, asshown in FIG. 5C.

Bone fusing implants 100A or 100B or 200 or 400 or 500 are inserted intoopenings formed through the ilium 95 and the adjacent sacrum 96.Referring to FIG. 6A-FIG. 6C, openings 92 a, 92 b are formed through theilium 95 and the adjacent sacrum 96 (or through stacked adjacent bones90 a, 90 b) by inserting pins 302 a, 302 b via a pin guide tool 300,shown in FIG. 7 and described in U.S. Pat. No. 9,717,538, the contentsof which are incorporated herewith by reference. The relative position,distance, pin depth and orientation of pins 302 a, 302 b is set by thepin guide 300. After the insertion of pins 302 a, 302 b, the openings 92a, 92 b are dilated with a dilator. An example of a dilator is alsoshown and described in U.S. Pat. No. 9,717,538. Next, a tissue protectoris inserted over the dilator and the dilator is removed leaving the pin302 a or 302 b in place to form an opening to the ilium. Next, acannulated drill is passed through the tissue protector over each of thepins and drilled into the ilium to a desired depth. Next, for implants100A, 100B, a tap is used to tap threads in the formed opening 92 aprior to inserting implants. For implants 200, 400 or 500, a broach isimpacted into the bone to generate the opening pattern of implant 200,400 or 500, respectively. Next, the bone fusing implants 100A, 100B, or200 or 400, or 500 are inserted into the corresponding formed openings92 a, 92 b and the pin guides are removed. The steps are repeated forinserting pins for another implant.

Referring to FIG. 8A, FIG. 8B, FIG. 8C and FIG. 8D, bone fusing implant400 includes an elongated hollow body 410 that has a star-shaped crosssection, six elongated outer grooves 412, and six elongated threadedouter ridges 413 that alternate with the grooves 412. Elongated body 410also includes a central through opening 422 that extends the entirelength of the implant, a first segment 430 with cortical threads 432 onthe outer ridges 413, a second segment 440 with cancellous threads 442on the outer ridges 413, a top segment 420 that has threads 425 on theouter ridges 413 that are thicker than the cortical threads 432, and abottom tip segment 445 that is tapered and self-cutting. Corticalthreads 432 are closely spaced. Screws with cortical threads are usedfor fixation of cortical (compact) bone. Cancellous threads 442 arewidely spaced. Screws with cancellous threads are designed for fixationof cancellous (porous) bone. Since cancellous bone is much less densethan cortical bone, the screw threads are spaced further apart, leavingspace for more bone in between each thread. In one example, implant 400has a length of 35 mm and a diameter of 12 mm. The segment 430 with thecortical threads 432 on the outer ridges 413 has a length of 30 mm,which corresponds to the width of the cortical bone 90 a. The segment440 with the cancellous threads 442 on the outer ridges 413 has a lengthof 5 mm, which corresponds to the width of the cancellous bone 90 b.Central opening 422 includes a top portion 422 a and a lower portion 422b and the lower portion 422 b has a smaller diameter than the topportion 422 a. The star-shaped elongated body 410 has increased outersurface area due to the surface areas provided by the alternating ridges413 and grooves 412. The increased outer surface area contributes tobetter joint fixation by minimizing micro-motion and therefore improvingbone fusion. In one example, implant 400 is made of a solid titaniumrod, while grooves 412 are porous. The threaded portions 425 and 442 ofthe elongated body 410 extend only on the protruding apexes of the outerridges 413, as shown in FIG. 8C and FIG. 8D.

Referring to FIG. 9A, and FIG. 9B, bone fusing implant 500 includes anelongated hollow threaded body 510 that has a star-shaped cross section,six elongated outer grooves 512, and six elongated threaded outer ridges513 that alternate with the grooves 512. Elongated body 510 alsoincludes a central through opening 522 that extends the entire length ofthe implant, a first segment 530 with cortical threads 532 on the outerridges 513, a second segment 540 with cancellous threads 542 on theouter ridges 513, a top segment 520 that has threads 525 on the outerridges 513 that are thicker than the cortical threads 532, and a bottomtip segment 545 that is tapered and self-cutting. Cortical threads 532are closely spaced, whereas cancellous threads 542 are widely spaced. Inone example, implant 500 has a length of 200 mm and a diameter of 12 mm.The segment 530 with the cortical threads 532 on the outer ridges 513has a length of 80 mm. The segment 540 with the cancellous threads 542on the outer ridges 513 has a length of 100 mm. In one example, implant500 is made of a solid titanium rod, while grooves 512 are porous. Thethreaded portions 525 and 542 of the elongated body 510 extend only onthe protruding apexes of the outer ridges 513. In other embodiments, thelength of implant is in the range of 10 mm to 200 mm. In someembodiments, bone fusing implants 400 or 500 further include fenestratedconfigurations 115, 216 a, 216 b, as was shown and described in theembodiments of FIG. 2A and FIG. 4A, respectively.

Referring to FIG. 10A-FIG. 10D bone fusing implant 400 is inserted intobone openings 93 a-93 d formed into the joint line between the ilium 95and the adjacent sacrum 96 along direction 82, as shown in FIG. 10B.Referring to FIG. 11A-FIG. 11D, bone fusing implant 500 is inserted intobone opening 93 e formed across the joint line between the ilium 95 andthe adjacent sacrum 96 along direction 83, as shown in FIG. 11A. Boneopenings 93 a-93 d or 93 e are formed by inserting pins 302 a, 302 b viaa pin guide tool 300, shown in FIG. 7 and described in U.S. Pat. No.9,717,538, the contents of which are incorporated herewith by reference.The relative position, distance, pin depth and orientation of pins 302a, 302 b is set by the pin guide 300. After the insertion of pins 302 a,302 b, the openings 93 a-93 d or 93 e are dilated with a dilator. Anexample of a dilator is also shown and described in U.S. Pat. No.9,717,538. Next, a tissue protector is inserted over the dilator and thedilator is removed leaving the pin 302 a or 302 b in place to form anopening. Next, a cannulated drill is passed through the tissue protectorover each of the pins and drilled into the ilium to a desired depth.Next, a broach is impacted into the bone to generate the opening pattern320 of implant 400 or 500, shown in FIG. 12A. Next, the bone fusingimplants 400, or 500 are inserted into the corresponding formed openings93 a-93 d, or 93 e, respectively, as shown in FIG. 12B, and the pinguides are removed. In this embodiment, there is a slight clearancebetween the inner surface of the bone openings and the threaded ridges413 and 513 of implants 400 and 500, respectively. In other embodiments,implants 400 and 500 are threaded directly into the formed bone openings93 a-93 d, or 93 e. In these cases, a pilot opening is formed into thebone and the tips 445 and 555 of the implants 400, 500 are used to startthreading the implants into the bone openings. In one example, the pilotopening has a diameter of about 3.2 mm. In other embodiments, a tap isused to tap threads in the formed bone opening prior to inserting andthreading implants 400, 500 into the bone openings.

Among the advantages of this invention may be one or more of thefollowing. The recessed grooves 412, 512 in the implant cross-sectionact as channels for material evacuation if the screw is inserted withjust a pilot opening. Improved material evacuation can lead to easierinsertion by decreasing the required torque. Regardless of the insertionmethod, the implant can always be threaded out for removal. This is animprovement over currently existing prior art implants that can only beimpacted in. Pulling out an impacted prior art implant during a revisionsurgery is usually difficult. Gaps formed in the threads by the recessedgrooves create multiple points along the length of the screw that caninitiate cutting into the bone for removal, if the implant was initiallyimpacted into position.

Several embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A bone fusing implant device comprising: anelongated body extending along a longitudinal direction, and comprisingone or more elongated grooves extending along the longitudinal directionon an outer surface of the elongated body and one or more elongatedridges alternating with the one or more elongated grooves and extendingalong the longitudinal direction on the outer surface of the elongatedbody; wherein the elongated body comprises a first segment having anouter surface with cortical threads, a second segment having an outersurface with cancellous threads, a top segment and a bottom segment,wherein the first segment is configured to engage a cortical bone withthe cortical threads and the second segment is configured to engage acancellous bone with the cancellous threads; wherein the corticalthreads and the cancellous threads are formed on the one or moreelongated ridges and do not extend into the one or more elongatedgrooves.
 2. The device of claim 1, wherein the top segment is adjacentto the first segment along the longitudinal direction and comprises anouter surface with cortical threads that are thicker than the corticalthreads of the first segment, and wherein the bottom segment is taperedand adjacent to the second segment along the longitudinal direction andcomprises a self-cutting tip.
 3. The device of claim 1, wherein theelongated body further comprises a central opening extending along thelongitudinal direction through the elongated body's center and thecentral opening comprises a top portion and a bottom portion and whereinthe bottom portion comprises a smaller diameter than the top portion. 4.The device of claim 3, wherein the elongated body further comprises oneor more through-openings that extend horizontally and intersect with thecentral opening.
 5. The device of claim 1, wherein the elongated bodycomprises a star-shaped cross-section and the elongated grooves arearranged 60 degrees apart from each other around the elongated body. 6.The device of claim 1, wherein the first segment has a length equal tothe cortical bone's length and the second segment has a length equal tothe cancellous bone's length.
 7. The device of claim 1, wherein theelongated grooves comprise a porous structure.
 8. The device of claim 4,wherein the elongated body further comprises bone material inserted intothe top portion of the central opening and funneled outwardly throughthe one or more horizontally extending openings.
 9. The device of claim8, wherein the bone material comprises one of bone graft, bone putty,stem cells, autograft bone, or allograft bone.
 10. The device of claim1, wherein the elongated body comprises one of bone,polyetheretherketone (PEEK), Nitinol, metals, titanium, steel, metalcomposites, biodegradable materials, collagen matrices, syntheticpolymers, polysaccharides, calcium minerals, calcium salts, orcomposites containing calcium or phosphorous naturally or man-made. 11.A method for bone fusing comprising: providing an implant devicecomprising an elongated body extending along a longitudinal direction,wherein the elongated body comprises a first segment having an outersurface with cortical threads, a second segment having an outer surfacewith cancellous threads, and wherein the first segment is adjacent tothe second segment along the longitudinal direction; engaging a corticalbone with the cortical threads of the first segment; engaging acancellous bone with the cancellous threads of the second segment;wherein the elongated body further comprises one or more elongatedgrooves extending along the longitudinal direction on an outer surfaceof the elongated body and one or more elongated ridges alternating withthe one or more elongated grooves and extending along the longitudinaldirection on the outer surface of the elongated body, and wherein thecortical threads and the cancellous threads are formed on the one ormore elongated ridges and do not extend into the one or more elongatedgrooves.
 12. The method of claim 11, further comprising forming anopening extending into the cortical bone and the cancellous bone andinserting and threading the implant device into the opening in order toengage the cortical bone with the cortical threads of the first segmentand the cancellous bone with the cancellous threads of the secondsegment.
 13. The method of claim 12, further comprising impacting abroach into the opening to generate an opening pattern matching thecross-section of the elongated body prior to inserting and threading ofthe implant device into the opening.
 14. The method of claim 12, whereinthe opening is formed by drilling a pilot opening into the cortical boneand the cancellous bone and then inserting and threading the implantdevice into the pilot opening.
 15. The method of claim 12, furthercomprising using a tap to tap threads in the opening prior to insertingand threading the implant device into the opening.